Power tools are often required to operate in different speed modes. For example, when a drill driven by a motor is used for drilling holes, high speed operation is required, and when it is used for turning screws, low speed operation is required. Speed control is commonly provided by a speed reduction mechanism such as a planetry gearbox. Multiple stages are provided in the gearbox to achieve the desired maximum speed and minimum speeds. However, adding stages to the gearbox is costly in terms of material and assembly costs and each stage introduces additional losses due to friction etc, which reduces the work time from a single charge of the DC power source (battery).